Apparatus for testing operation of an emerceny valve

ABSTRACT

Apparatus for testing an emergency valve in which a valve member ( 10 ) is movable by fluid-operated actuator ( 11 ) between a normal (open or closed) position and an emergency position (closed or open respectively). The apparatus comprises partial stroking means including means ( 32, 23, 22  to  13 ) for initiating emergency movement of the valve from its normal towards its emergency position, and means ( 13, 14 ) for returning it from a predetermined position intermediate the normal and emergency positions at its normal operating speed. The apparatus includes means for detecting the loss of the controlling electrical signal to the valve and a means ( 51 ) for detecting the correct operation of the valve and its associated operating components by measuring the pressure of fluid being released from or being applied to the actuator ( 11 ).

[0001] The present invention relates to means for testing operation ofan emergency valve such as an emergency shut down or isolation valvewhere, in emergency, the valve closes or an emergency blow-down valvewhere, in emergency, the valve opens.

[0002] The invention will be described with particular reference toemergency shut down valves which are used, for example, in processingindustries such as oil refineries or oil rigs, the valve being providedin a pipeline, the arrangement being such that in the event of anemergency, the valve will close. However, the emergency valve may be anemergency isolation valve, which, in an emergency, shuts down andisolates part of a process or an emergency blow down valve which, in anemergency, opens to pass air or other fluid to, for example, blow downthe process.

[0003] Reference may be made to the following products: MetsoAutomation, Neles ValveGuard: Emerson Process Management, FisherRosemount DVC. 600: Masoneilan, Smart Valve Interface SVI.

[0004] Reference may also be made to the applicant's earlier UK patentspecification 2,346,672, UK patent specification 2,332,939, and UKpatent specification 2,338,051.

[0005] Whilst we shall describe the invention with particular referenceto emergency valves for use in isolating the flow of oil, it will beunderstood that other valves controlling the flow of other fluidscomprising a liquid or gas may be tested by means according to theinvention. The invention may be used in a variety of environments. Forexample, when the invention is used in a chemical works, the emergencyshut down valve or emergency blow-down valve may be used in a chemicalpipeline. Similarly the valve may be used in a gas pipeline, either in achemical works or remotely in a pipeline remote from the works.

[0006] One of the difficulties with such emergency valves is thatparticularly where an oil refinery or oil rig is in continuousoperation, the cost of shutting any particular line whilst carrying outmaintenance work is extremely high, and, the emergency valves are notmoved between maintenance intervals, which may be several years. As aconsequence, over that period of time, because of the deposit of dirt orother material, the emergency valve may become stuck and not be operablein an emergency. It is highly desirable to be able to test the emergencyvalves at more frequent intervals to ensure that they are operable andit is preferable to test for proper operation of the valve and to testfor example to determine the degree of deposit of dirt or other materialwithout closing down the oil pipeline in which they are mounted.

[0007] Emergency valves comprise a variety of forms, for example, gatevalves, butterfly valves, rotary or ball valves. The emergency valve isoperated by an actuator. One method of operation of the actuator useshydraulic or gas pressure to retain the valve in its normal position egclosed or open. In the case of a single acting actuator, when theemergency valve is to be shut (open), the hydraulic or gas pressure isreleased and a metal spring or other mechanism closes (opens) the valve.In the case of a double acting actuator, the pressure medium controllingthe actuator is redirected to close (open) the valve. The application ofthe hydraulic or gas pressure is normally controlled by one or moreelectrically controlled solenoid valves, the electrical signal (voltage)being provided by an electrical control line. Any interruption of theelectrical signal operates the solenoid valves to release or divert thehydraulic or gas pressure and hence moves the valve to its emergencyposition ie closed (open).

[0008] When testing the operation of an emergency valve, it is commonpractice for a device to be included in the emergency valve controlcircuit to be operated in order to test the valve, this has the effectof slowing down the normal operation of the emergency valve. Thus wherefor example the valve is operated pneumatically, there is provided aproportional controller, which allows the release of successive smallamounts of gas/fluid from the actuator, which allows small controlledmovements of the actuator. There is also provided a position detector,which detects the position of the valve stem or other part of the valveand which in theory prevents the valve closing completely. (However, inpractice, if the emergency valve is stuck, the controller releasesgas/fluid until movement is detected by the position detector and mayrelease all or substantially all of the gas at which point if the valveunsticks, it will close completely).

[0009] FIGS. 1A-D illustrate the operation of various emergency valvesin different circumstances.

[0010] In FIG. 1A, the vertical lines illustrate the valve open positionand the valve closed position. In normal emergency use, the emergencyvalve when operated closes in less than one second and there is fullvalve travel in that period of time.

[0011] In FIG. 1B is illustrated the equivalent for the test arrangementdescribed above in which release of successive small amounts of gas orhydraulic fluid allows small movements of the actuator. In this case,the period of time between the valve being fully open and the valvestopped at part travel is greater than 10 seconds and as can be seen thevalve travels to an intermediate point between open and closure and thenreturns to the open position.

[0012]FIG. 1C illustrates a situation in which the emergency valve isoperated as if there is an emergency condition, so that the valve movesat normal speed (ie the total time from valve open to valve closed wouldbe less than one second) but is stopped at a point before the valve isfully closed as illustrated by the dotted vertical line. In theillustrated example the part valve travel takes place over less than0.25 seconds.

[0013]FIG. 1D illustrates an arrangement similar to FIG. 1C andillustrates in more detail the left hand section of that Figure, wherebythere is part valve travel over a time which is less than 0.25 seconds,and the valve is then immediately (without delay) returned from the partopen position to the filly open position.

[0014] When operating under emergency conditions, an emergency valveevacuates most or all of the gas from the actuator substantiallyinstantaneously and so this known test technique, which slowly releasesthe gas, does not replicate those conditions. Whilst this test mayenable some observation of the operation of the valve and hence somesense of any difficulties there may be in its operation, it is not anaccurate test of the operation of the emergency valve in an emergency.Furthermore, only very limited information may be ascertained from theposition detector.

[0015] We shall describe hereafter an arrangement in which the emergencyvalve may be tested for operation by partially stroking the valve to apredetermined point and then returned to its normal position, it beingascertained that so long as the emergency valve is shown to move, it isnot necessary to close it fully since the initial movement of the valveis only necessary to prove that the valve is free to move and providesevidence that the valve would close completely. We shall also describe,means for comparing operation of the emergency valve during a fullemergency closure of the valve assembly with the initial emergency testclosure of the valve and thereby to determine its performance.

[0016] The present invention provides apparatus for testing an emergencyvalve and its associated controlling components, said emergency valvecomprising a valve member movable during emergency operation by anactuator between a first (normal i.e. open or closed) position and asecond(emergency i.e. closed or open respectively) position at a normaloperating speed under emergency conditions, said testing apparatuscomprising means for initiating emergency operation of the valve so thatthe valve member begins to move from the first position towards thesecond position at said normal operating speed and means for immediatelyinitiating reversal of the valve member, when it reaches a positionintermediate its first and second positions whereby to partially strokethe valve.

[0017] Thus the emergency valve is tested at its normal operating speedand this provides a more accurate indication of the state of theemergency valve than operating it unnaturally slowly.

[0018] We shall describe an arrangement in which the partial strokingand hence the testing of the valve is carried out at its normal speed ofoperation rather than the reduced speed which has hitherto been thoughtnecessary.

[0019] Preferably, therefore, we start the emergency procedure for theemergency valve in the normal way and return it before it reaches itsemergency position.

[0020] Means may be provided to analyse the pressure of said fluid toprovide information as to whether the emergency valve is operatingsatisfactorily. This may include determining whether the valve willclose, but may also determine other factors, such as dirt or corrosionwhich slows operation of the actuator/valve, and may determine whetherthe solenoid valve or other components linked to the pressure source areoperating and may also be used to predict problems in the future.

[0021] The time taken for different emergency valves to open or closewill vary depending upon their size, material flowing through them, andthe actuator driving them, and so to provide for this, in a preferredaspect, the testing apparatus may include a computer, relay means andvariable timing means.

[0022] Where the emergency valve is of a type where application of anelectrical signal to a control line keeps it in its normal position, andan absence of that signal causes it to move to the emergency positionby, for example, a spring, said control line is adapted to pass throughsaid testing means from an input terminal to an output terminal, saidinput terminal and output terminal being connected electrically throughrelay means and there is provided variable timing means operable toapply power to said normally closed relay to open said relay for apredetermined time to partially close/open the valve.

[0023] In many applications, fail safe redundancy is required and inthat case a second timing means may be provided in series with saidfirst mentioned timing means, so that even if one of the timing meansfails and continues to apply power to said normally closed relay meansto keep it open, the other timing means will interrupt the power supplyand cause the valve to move to its normal position.

[0024] Similarly, said relay means may be coupled in parallel with asecond relay means, said second relay means being controlled in the sameway as the first relay means by one or two of said timing means,whereby, if either of said relay means fails in said open position, theother relay means will close to electrically connect said input andoutput terminals and cause the valve to move to its normal position.

[0025] In certain circumstances it might be possible to operate saidtesting means successively in the time interval before said emergencyvalve has moved fully to its emergency position and in that waysuccessive strokes might cause the emergency valve to move fully to itsemergency position.. To avoid this, there may be provided a furthertiming means to interrupt operation of the test for a period of timesufficient for a complete cycle of operation to take place.

[0026] One of the merits of using the control line to partially strokethe emergency valve is that there is no interference with the mechanismof the emergency valve and, indeed, the size; type of operation, etc, ofthe valve is irrelevant. Thus a single type of testing means may beprovided for partially stroking any type of emergency valve. It issimply necessary to adjust the variable timing means to suit therelevant emergency valve.

[0027] In a particularly preferred aspect of the invention, means mayalso be provided to analyse the operation of the valve. For example,where the valve is a pneumatically or hydraulically actuated valve, thepressure of the air or hydraulic fluid applied or released (in the caseof a single acting actuator) to the actuator of the emergency valve maybe measured. We have found that, unexpectedly, from such pressuremeasurements, the operation of the valve and its operating componentsmay be analysed and problems identified.

[0028] In such a way, it is possible to test not only for operation ofthe actuator/emergency valve assembly, in the sense as to whether theemergency valve will close, but also other factors, such as dirt orcorrosion which slows operation of the actuator/emergency valve, whetherthe solenoid valve or other components linked to the pressure source areoperating and which may be used to predict problems in the future.

[0029] A preferred embodiment of the invention will now be described byway of example and with reference to the accompanying drawings in which:

[0030]FIG. 2 is a diagrammatic view of an emergency valve in a pipelinewith a single hydraulic or pneumatic acting actuator connected to atesting means for partially stroking the emergency valve, the systembeing shown in a normal condition with the emergency valve open.

[0031]FIG. 3 shows traces of pressure readings taken from a pressuretransducer connected to the fluid input/output of the actuator.

[0032] Referring to FIG. 2 there is shown an emergency valve 10 in apipeline 17, the emergency valve being arranged so as to close off thepipeline 17(which may be for example an oil or chemical or gas pipeline)to prevent the flow of fluid through the pipeline in an emergency. Thevalve 10 is operated by a single acting actuator 11, the actuator beingheld open by gas or hydraulic fluid applied at pressure to one side of apiston in a piston/cylinder unit of the actuator. The gas or hydraulicpressure fluid from a fluid pressure supply 12 is applied to theactuator 11 via a valve 13 controlled by a solenoid 14 (or otherelectrically controlled means). The solenoid valve 13, in a firstposition, applies the pressure from the fluid pressure supply 12 to thepiston/cylinder unit of the actuator 11 via a line 15 and in a secondposition isolates the piston/cylinder unit 11 from the gas or hydraulicpressure supply 12 and connects it to exhaust at 16. In the secondposition of the solenoid controlled valve 13, with the piston/cylinderunit of the actuator 11 connected to exhaust and in the absence theapplication of gas or hydraulic pressure to hold the piston of thepiston/cylinder unit in such a position as to hold the valve 10 in theopen position, the emergency valve 10 immediately moves from its normalposition (open in this example) to its closed position by means of ametal spring 18 or other means acting on the rear of the piston of thepiston/cylinder unit, the arrangement described above is well known.

[0033] The speed of movement of the emergency valve varies depending onthe emergency valve. In some emergency valves the operation may be slowand may take a number of seconds from normal (open) to emergency (close)but in many such emergency close valves the operation is rapid and thetime from being fully open to fully closed may be as little as onesecond.

[0034] The solenoid valve 13 is held in the position in which pressurefrom pressure supply 12 is applied to the piston/cylinder unit of theactuator 11 when an electrical voltage is applied on an electricalcontrol line 19 and when the voltage on the electrical control line 19falls to zero, then the solenoid valve moves to the position in whichthe piston/cylinder unit is isolated from pressure gas or hydraulicpressure from the supply 12 and connected to exhaust 16. The system istherefore failsafe in that failure of the electrical supply to thesolenoid valve, will cause the emergency valve 10 to be closed by themetal spring 18 or other means.

[0035] In non fail safe modes the solenoid valve 13 is held in theposition in which pressure is applied to the piston/cylinder unit 11when an electrical voltage is applied on electrical control line 19 andwhen the voltage on the electrical control line 19 rises, then thesolenoid valve moves to the position in which the piston/cylinder unit11 is isolated from gas or hydraulic pressure from the supply 12.

[0036] Referring to FIG. 2 it will be seen that a test control means 21is provided with an output terminal 22 connected to the line 19 and aninput terminal 23 connected to an electrical control line 25, which line25 is connected to an electrical voltage. The line 25 would normally beconnected directly to the solenoid 14 but in this arrangement the testcontrol means 21 has been connected into the line 25/19.

[0037] Thus electrical power from the electrical control line 25 passesthrough the testing control means 21 which controls the application ofthat electrical power to solenoid valve 14 via line 19.

[0038] The control line 25 passes through the testing control means 21from the input terminal 23 to an output terminal 22, the input terminaland output terminal being connected electrically through relays 203 andthere is provided variable timing means 202 to apply power to saidrelays 203 to open said relays for a predetermined time to interrupt thesupply on the line 19 to thereby cause the solenoid valve 13 to exhaustthe pressure fluid from the actuator 11 and allow the actuator 11 tomove the valve 10 to a partially closed position under the action ofspring 18.

[0039] Failsafe operation is normally required and thus a second timingmeans is provided in series with the first timing means so that even ifone of the timing means fails and continues to apply power to thenormally closed relays to keep it open, the other timing means willinterrupt the power supply and cause the emergency valve to move back toits normal position.ln certain circumstances it might be possible tooperate the test means successively in the time interval before theemergency valve has fully moved to its emergency position and in thatway successive attempts to operate the testing control means may causethe emergency valve to fully move to its emergency position. To avoidthis there may be provided a further timing means to interrupt operationof the test for a period of time sufficient for a complete cycle ofoperation to take place.

[0040] A test initiation means 24 may be provided connected to thetesting control means 21. The test means 24 comprises a start button 26and an output indicator, which illustrated in the present instance hasbeen provided by two lamps 27 and 28. However other outputs may beprovided, for example, a VDU screen to carry a message relating to thefault detected.

[0041] The line 25 is connected through an interface 30 (well known inthis type of application) which is in turn connected to a computer 31,the power line 25 passing through the interface 30 to a safetyprogrammable logic controller 32. The controller 32 is connected to adistributed control system 33 by line 34 and the distributor controlsystem 33 is connected to computers 35 in a control room 36. Theinterface 30 computer 31 controller 32 and control system 33 may beprovided in a conventional arrangement in an electrical room 37. The DCpower is provided on line 25 either directly from the controller 32 orvia the interface 30, and through the testing control means 21 to theline 19 and thence to the solenoid 14 of valve 13. As is well known inthis field, there may be provided superimposed on the DC signal on line25 which allows communication between the DCS 33 via the interface 30and to the testing control means 21. The signals may pass in bothdirections. Thus the testing control means 21 may provide a signal onthe line 25 (as will be explained later) which is extracted by theinterface 30. The interface 30 may provide one of two signals, that isan alarm signal on line 38 or an OK signal on the line 39 to thedistributed control system 33. Furthermore there may be providedseparate signal lines between the testing control means 21 and thecontrol system 33, these lines being illustrated at 41, 42, 43.

[0042] We will now describe the set-up and testing procedure.

[0043] Set-up Procedure

[0044] The set up procedure may be initiated in a number of ways: from aportable computer device 200 connected to the control means 21, or froma computer 31 via a superimposed signal on control line 25,

[0045] As described above, the circuitry in device 21, timing 202 andrelay means 203 are provided to control the application of theelectrical power from the control line 25 via device 21, line 19 thenceto solenoid 14 of valve 13 keeping the emergency valve 10 in its normalposition

[0046] When it is desired to set up the emergency valve 10 to define anormal signature A (as shown in FIG. 3) a signal is passed from theportable computer device 200, or from a computer 31 via a superimposedsignal on control line 25,

[0047] The effect of that is to interrupt the relay means and set thetiming means 202 at a default long time. The opening of the relay means203 disconnects the voltage from line 19. As a result in FIG. 2, thesolenoid valve 13 will be switched to isolate the pressure supply 12from the piston cylinder unit of the actuator 11 and the valve 10 willbegin to move to its emergency position under the action of spring 18.During this time an output signal is generated and passed from thepressure device 51 on line 52 to the control means 21. Once the pressurehas reached atmospheric, and the timing means has timed out, the relaymeans 203 changes state, which restores the power signal to line 19 andhence to solenoid 14 of valve 16 which reapplies pressure fluid to theactuator and the emergency valve 10 returns to its normal position. Inthe event that the electrical signal is removed by the safetyprogrammable logic controller 32 this is detected by the circuitry indevice 21 and a full stroke close signature is captured using device 51.

[0048] The pressure signal A (shown in FIG. 3) produced by the sensor 51during these processes is stored in an onboard computer 201. An analysisof the signature A will show the change in the pressure applied to theactuator from full system pressure to atmospheric over the time it takesfor the emergency valve 10 to fully close.

[0049] To produce a partial closure of the emergency valve based on thisinformation, a predetermined percentage closure figure (e.g. 10%, 20%,30%) is chosen and input into portable computer device 200, or from acomputer 31 via a superimposed signal on control line 25, andtransmitted to the computer in control means 21. The effect of this isto set the timing means 202 at a new time less than the default time andcalculated to provide the predetermined percentage closure figure. Theopening of the relay means 203 then disconnects the voltage from line19. As a result in FIG. 2, the solenoid valve 13 will be switched toisolate the pressure supply 12 from the piston cylinder unit of theactuator 11 and the valve 10 will begin to move to its partial strokeposition under the action of spring 18. During this time an outputsignal is generated and passed from the pressure device 51 on line 52 tothe control means 21. Once the timing period is up, the relay means 203are changes state, which restores the power signal to line 19 and henceto solenoid 14 of valve 16 which reapplies pressure fluid to theactuator and the emergency valve 10 returns to its normal position. Thepartial stroke signature B (shown in FIG. 3) is then stored as astandard against which further partial stroke tests can be compared.

[0050] Test Procedure

[0051] The test procedure may be initiated in a number of ways: from theportable computer device 200, or from the computer 31 via a superimposedsignal on control line 25, from a signal from the DCS 33 via line 43 orby the push button 26 FIG. 2 in the initiation means.

[0052] When, after the signatures A and B have been determined andstored, it is desired to test the emergency valve 10 to compare thesignature at a later point in time with the stored signature B, apartial closure test is initiated by a signal from the portable device200, or from the computer 31 via a superimposed signal on control line25, from a signal from the DCS 33 via line 43 or by the push button 26FIG. 2 as described above.

[0053] The effect of this is to interrupt the relay means 203 and setthe timing means 202 (although in practice the timing means will bepreset with the time corresponding to the percentage closure desired).The opening of the relay means 203 disconnects the voltage from line 19.As a result in FIG. 2, the solenoid valve 13 will be switched to isolatethe pressure supply 12 from the piston cylinder unit of the actuator 11and the valve 10 will begin to move to its predefined partial strokeposition stored in computer 201 in control means 21 FIG. 2, under theaction of spring 18. During this time an output signal is generated andpassed from the pressure device 51 on line 52 to the control means 21.Once the timing period set by the timing means to provide the desiredpartial stroke is reached, the relay means 203 are changes state, whichrestores the power signal to line 19 and hence to solenoid 14 of valve16 which reapplies pressure fluid to the actuator and the emergencyvalve 10 returns to its normal position. The pressure signal producedduring this partial stroke test is compared with the signature B bycomputer 201 of control means 21 FIG. 2, or against previously helddata.

[0054] Frequent operation of the apparatus to partially move theemergency valve 10 towards its emergency position (ie partially strokethe emergency valve 10) in this way can be used to plot the change ofeffectiveness of the actuator or its associated equipment to close theemergency valve.

[0055] One of the advantages of the arrangement of control means set outabove is that it can be simply inserted into the electrical powercontrol line 25/19. This is particularly useful where, for example, thevalve 10 is remote, for example, is provided on the seabed and allowsready application of the testing means to other types of emergencycontrol valve, for example, emergency control valves with double actingactuators, or with electrical or Hydraulic actuators.

[0056] In many circumstances, the solenoid controlled valve 13, whenoperated to exhaust the hydraulic or pneumatic pressure from within theactuator 11 is sufficiently large as to exhaust the fluid at asufficiently rapid rate. In some circumstances, however, particularlywhere the actuator 11 is large, it may be desirable to provide a largerexhaust outlet than exhaust 16 that the solenoid valve 13 can normallyprovide. In this case one can use an exhaust valve 48 referred to as avolume booster/quick exhaust valve 48. Such exhaust valves are wellknown. The exhaust valve 48 is provided in the line 15 adjacent thehydraulic fluids/air inlet/outlet of the actuator 11 and between theactuator 11 and the solenoid valve 13 and includes an exhaust outlet 49.This exhaust outlet 49 may be particularly large. The exhaust valve 48is operated by means of the pressure differential between the pressurein the pipe work on the two sides of the exhaust valve 48. When thepressure of fluid or gas on the side of the valve 48 closest to thesolenoid valve 13 becomes less than the pressure on the opposite side ofthe valve 48, then the valve 48 opens the actuator 11 to the exhaust 49.Thus, in use, when the solenoid valve 13 opens to exhaust hydraulicfluid/gas from the actuator 11, the pressure in the pipe 15 between thevalves 48 and 13 will fall below that on the opposite side of the valve48 and the valve 48 will immediately open to dump the pressure at a morerapid rate.

[0057]FIG. 3 shows various traces of the pressure (detected by pressuresensor 51) exhausting from or being applied to the actuator 11. Thevertical axis is of the pressure sensed by pressure sensor 51 and thehorizontal axis is time.

[0058] The base trace A in FIG. 3, is a trace of the pressure sensed bysensor 51 during a complete emergency operation of the emergency valve.caused by The electrical power is removed from line 19 to solenoid valve13 for a sufficient time to allow the emergency valve 10 to move to itsemergency position; during this process a reading is taken from thepressure transducer 51 FIG. 2. The base trace A is used as a comparisonagainst other tests and provides a basic fill emergency operationpressure signature.

[0059] The form of the trace A is therefore as follows: at 100 theelectrical signal is removed from solenoid valve 13 and there is aninitial rapid pressure decay over region 101 via the solenoid valve 13and the quick exhaust valve 48 FIG. 2, as air/hydraulic fluid isexhausted from the actuator 11. After a period of time (ie at the end ofregion 101, at point 102) which may be due to inertia and/or the pointat which the pressure in the system reaches a point whereby it cannothold back the spring 18 in actuator 11, the piston of thepiston/cylinder unit of the actuator 11 begins to move. The springbegins to assist the air to exhaust from the actuator and a flatteningoff or temporary increase of the pressure decay occurs. This provides a“hump” region in the pressure trace at 102. Thereafter the emergencyvalve moves fully to its emergency position, eg to full closure at 104.

[0060] After reapplying power to line 19 to open solenoid valve 13 andrepressurise actuator 11 and hence move valve 10 to its normal position,a partial stroking test is carried out to establish a part valve closurebase trace B, (indicated by the dash/dot line). Thus the electricalsignal on line 19 is removed for a time allowing the emergency valve 10to begin moving to its emergency position., and as already explainedafter a predetermined time controlled by timing means, the electricalsignal to solenoid valve 13 FIG. 2 is reinstated, to allowing the systempressure to pressurise the actuator 11 and return the valve 10 to itsnormal position.

[0061] Referring to the trace B shown in FIG. 3, initially when theelectrical signal is removed from the solenoid valve 13 at 100 there isthe same initial rapid pressure decay at region 102 as in the case oftrace A. As in the case of trace A, once pressure in the system reachesa point 102 the pressure trace initially follows trace A along region103.

[0062] At the point 105, the timing means operate the relay means toreapply power to line 19 and hence to the solenoid valve 13 which movesto reapply system pressure to the actuator 11 and so the pressure traceB begins to increase along the line at region 106. Approximately atpoint 107, the pressure equals the initial pressure.

[0063] The partial stroking base trace B is used as a comparison againstother tests and provides a partial test signature.

[0064] Should the emergency valve or its associated control equipmentdevelop a fault it has been found that an abnormal trace is provided bythe pressure transducer 51.. The trace C illustrates the pressure signalprovided by the pressure sensor where the emergency valve exhibits afirst fault. Trace C illustrates the situation where the piston of thepiston cylinder unit of the actuator 11 does not move when pressure isreleased from the actuator 11. Thus if the piston remains stuck in thenormal, non emergency position, (or even if it only moves slowly orslightly) then initially as can be seen the pressure trace C follows therapid pressure decay 100, 101, 102 of pressure trace A. Beyond point 102the pressure trace continues downwards in a continuous manner 108 (iethere is no “hump” 103) to the point 104 where all of the air orhydraulic pressure within the actuator is exhausted.

[0065] Trace D shows the pressure signal for a partial stroke test wherethe piston is stuck. Pressure trace D follows that of pressure trace Cbetween 100, 101, 102 and 108, ie does not include the “hump” ofpressure trace A but continues downwards like pressure trace C until thesolenoid valve 13 is actuated at 109 to reapply pressure to the actuator11 at which point the pressure trace increases as shown at 110.

[0066] It will be noted that the area of the trace including the points102, 103, 105, 108, 109 is particularly relevant to an analysis ofproblems associated with the emergency valve and its actuator, Similarlythe area of trace from 100 to 102 may be used to identify problemsassociated with the emergency valves control means such as the solenoidvalve and or the quick exhaust/volume booster.

[0067] As is clear from FIG. 2, the pressure signal is passed along line52 to the test control means 21 the signal is analysed by test controlmeans 21 by means of computer 201 and passes the relevant signal to theunit 24 where an error may be indicated by illumination of the lamps 27and 28. Thus if the problem associated with the emergency valve is of arelatively minor nature (for example, the piston moves slightly moreslowly than usual and hence, for example, the “hump” 103 will beslightly different from the base trace B, then a combination of lampsmay be illuminated. If, however, there is a more serious problem, forexample the piston is stuck and therefore trace D is detected, then asecond lamp 28 may be illuminated to indicate that immediate action isrequired. Similarly the relevant information may be passed along line 25to the DCS 33 (to provide a signal on line 38) or alternatively alongline 42 or 41 to the DCS 33.

[0068] We have illustrated two traces C and D which indicate errors inoperation of the emergency valve. Other traces which indicate otherproblems may be determined and sample traces may be stored on a remotewebsite for access over the Internet by users of emergency valves. Thusthe user of an emergency valve may download from time to time from thewebsite a suite of traces illustrating various problems which, perhaps,have been encountered in use by other users of emergency valves, and mayuse these traces to analyse the traces provided by the relevantemergency valve during a partial stroking test.

[0069] The suite of traces may include traces which illustrate problemsassociated with dirt or corrosion which slows movement of the valve 10,whether the solenoid 14 or components linked to the pressure source 12are operating correctly.

[0070] Additional diagnostics are be obtainable by downloading to aportable data storage device 200, for analysis by a computer housing adiagnostics program, the data obtained from and stored in the computermemory in by means of local infrared source, or by a superimposed signalon line 25.

1. Apparatus for testing an emergency valve and its associatedcontrolling components, said emergency valve comprising a valve member(10) movable during emergency operation by an actuator (11) between afirst and a second position at a normal operating speed under emergencyconditions, said testing apparatus comprising means for initiatingoperation of the valve at emergency speed so that the valve memberbegins to move from the first position towards the second position atemergency speed and means (14, 13) for initiating reversal of the valvemember when it reaches a position intermediate its first and secondpositions whereby to partially stroke the valve, said actuator beingoperated by fluid, characterized in that said apparatus including means(21,51) to measure a parameter of the fluid applied to or exhausted fromthe actuator of the valve and/or associated controlling devices in thepipe-work connected to the actuator, and means (21) is provided toanalyse said parameter to thereby provide information as to whether theemergency valve and/or associated controlling devices in the pipe-workconnected to the actuator are operating satisfactorily, said means toanalyse including stored data relating to the parameter recorded duringan initial test operation of the emergency valve, and the means toanalyse is adapted to compare the data measured during a subsequent testwith the stored data.
 2. Apparatus as claimed in claim 1 in which theparameter is the pressure of fluid applied to or exhausted from theactuator of the valve and/or associated controlling devices in thepipe-work connected to the actuator.
 3. Apparatus as claimed in claim 1in which the parameter is the flow of fluid applied to or exhausted fromthe actuator of the valve and/or associated controlling devices in thepipe-work connected to the actuator.
 4. Apparatus as claimed in claim 1including means for comparing operation of the emergency valve (17)and/or associated controlling devices in the pipe-work connected to theactuator during the partial stroking of the valve with an initial testoperation of the valve at emergency speed and thereby to determine itsperformance.
 5. Apparatus as claimed in claim 4 further including meansfor comparing operation of the emergency valve (17) and/or associatedcontrolling devices in the pipe-work connected to the actuator during afull operation of the valve with the initial full operation test of thevalve at emergency speed and thereby to determine its performance. 6.Apparatus for partially stroking an emergency valve of the typecontrolled by an electrical signal on a control line, said emergencyvalve being operable by an actuator operated by fluid, said apparatuscomprising testing means (21,202,203,201) for connection to said controlline said testing means including means for removing the electricalsignal on said control line (13,14) for a period of time to cause saidemergency valve to initiate emergency operation of the valve at itsnormal emergency speed to move to a position intermediate an open and aclosed position and for then reapplying the electrical signal to reversethe valve, characterized in that said apparatus including means (21,51)to measure a parameter of the fluid applied to or exhausted from theactuator of the valve and/or associated controlling devices in thepipe-work connected to the actuator, and means (21) is provided toanalyse said parameter to thereby provide information as to whether theemergency valve and/or associated controlling devices in the pipe-workconnected to the actuator are operating satisfactorily, said means toanalyse including stored data relating to the parameter recorded duringan initial test operation, and the means to analyse compares the datameasured during a subsequent test with the stored data.
 7. Apparatus asclaimed in claim 6 in which, the testing means includes at least onevariable timing means and a relay means.
 8. Apparatus as claimed inclaim 6 in which the valve is operated by an actuator which is operatedby fluid pressure, said apparatus including means (21,51) to measure thepressure of fluid exhausted from or applied to the actuator and/orassociated controlling devices in pipe-work connected to the actuator 9.Apparatus as claimed in claim 6 in which the valve is operated by anactuator which is operated by fluid, said apparatus including means(21,51) to measure the flow of fluid applied to or exhausted from orapplied to the actuator of the valve and/or associated controllingdevices in pipe-work connected to the actuator
 10. Apparatus as claimedin claim 6 including means for comparing operation of the emergencyvalve (17) during the partial stroking closure of the valve assemblywith an initial test closure of the valve at emergency speed and therebyto determine its performance.
 11. Apparatus as claimed in claim 10further including means for comparing operation of the emergency valve(17) during a full emergency closure of the valve assembly with theinitial test closure of the valve at emergency speed and thereby todetermine its performance.
 12. Apparatus as claimed in claim 6 in whichthe emergency valve includes means whereby application of saidelectrical signal on said control line keeps the emergency valve open,and an absence of that signal causes it to be closed by a resilientmeans, said control line passing through said testing means from aninput terminal to an output terminal, said input terminal and outputterminal being connected electrically through a normally closed relay(203).
 13. Apparatus as claimed in claim 12 in which there is providedtimer means (21,202) operable to apply power to the control terminal ofsaid normally closed relay (203) to open said relay to partiallyclose/open the emergency valve.
 14. Apparatus as claimed in claim 13 inwhich timer means includes two timers (202) in series, so that even ifone of the timer fails and continues to apply power to said normallyclosed relay (203) to keep it open, the other timer will interrupt thepower supply.
 15. Apparatus as claimed in claim 14 in which said relaymeans (203) is coupled in parallel with a second relay means (203), saidsecond relay means having a control terminal connected to the controlterminal of said first relay (203), whereby, if either of said relaymeans fails in said open position, the other relay means will close toelectrically connect said input and output terminals.
 16. Apparatus asclaimed in claim 14 in which there is provided a further timer means(202) to interrupt operation of (13) for a period of time sufficient forthe emergency valve to return to its open position after partialclosure.
 17. Apparatus for stroking an emergency valve, at itsdesignated operating speed under emergency conditions, of the typecontrolled by an electrical signal on a control line (19), saidemergency valve being operable by an actuator operated by fluid, saidapparatus comprising means (21,202,203,201) for connection to saidcontrol line, to provide a means of removing the electrical signal tomeans (13,14) for a period of time to cause said emergency valve to movefrom its open to closed position and then to be reversed characterizedin that said apparatus including means (21,51) to measure a parameter ofthe fluid applied to or exhausted from the actuator of the valve and/orassociated controlling devices in the pipe-work connected to theactuator, and means (21) is provided to analyse said parameter tothereby provide information as to whether the emergency valve and/orassociated controlling devices in the pipe-work connected to theactuator are operating satisfactorily, said means to analyse includingstored data relating to the parameter recorded during an initial testoperation, and the means to analyse compares the data measured during asubsequent test with the stored data.